Quinoline, a widely distributed pollutant, and an industrial chemical, has recently been found to be a hepatocarcinogen in rats and mice, a coinitiator in mouse-skin bioassay with benzo(a)pyrene, and a mutagen in Salmonella typhimurium tester strains. However, the carcinogenicity of the methyl homologs of quinoline has not been examined, nor has the metabolism of this class of compound (aza-arenes) has been investiated in depth. We plan, in this study, 1) to determine the extent to which quinoline and related compounds occur in various environmental settings, 2) to assess their mutagenicity and carcinogenicity, so as to establish structure-activity relationships, and 3) to investigate their mode of action, as an approach to devising preventive measures. In a typical case, the metabolism of quinoline will be investigated in vitro (rat liver homogenate and primary cell culture) and in vivo (in the rat). From the resulting metabolite profile (HPLC/GLC), and identification of key metabolites, insight will be gained into the pathway of metabolic activation of this environmental agent. Screening of metabolites for mutagenic activity will allow us to pinpoint candidate activated species. This should provide us with a greater understanding of aza-arene metabolism, and indicate approaches to reducing the levels of these environmental agents which may bear on the etiology of human cancer.